PatchTheCVECVE-2026-52940: In the Linux kernel, the following vulnerability has been resolved: tun: zero the whole vnet header in tun_pu
CVE-2026-52940 is a medium-severity flaw (CVSS 5.5) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
In the Linux kernel, the following vulnerability has been resolved: tun: zero the whole vnet header in tun_put_user() tun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel without zeroing it. For a non-tunnel skb, virtio_net_hdr_tnl_from_skb() only initializes the first 10 bytes (sizeof(struct virtio_net_hdr)), leaving bytes 10..23 (num_buffers and the hash/tunnel fields) as stack garbage. An unprivileged user can set the vn
Why this priority
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.5 (Medium) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.2% (top 95%) |
| CISA exploited list | No |
| Published | 2026-06-24 |
| Last modified | 2026-07-08 |
Last updated 2026-07-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-52940?
linux kernel: upgrade to 6.18.36, 7.0.13. Exact commands for each OS are on this page.
Is CVE-2026-52940 being exploited?
CVE-2026-52940 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-52940 affect?
CVE-2026-52940 affects linux kernel. Severity is medium (CVSS 5.5). In the Linux kernel, the following vulnerability has been resolved: tun: zero the whole vnet header in tun_put_user() tun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel without zeroing it. For a non-tunnel skb, virti
How urgent is CVE-2026-52940?
Priority 26/100. On your watchlist
Software pages
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